1. Field
The present disclosure relates generally to aircraft and, in particular, to locating aircraft. Still more particularly, the present disclosure relates to a method and apparatus for locating aircraft in a water environment after an unintended encounter with the water environment.
2. Background
Aircraft are commonly used to transport people and cargo. Aircraft may fly over various types of terrain when traveling from a start location to a destination location. The terrain may include flat land, mountains, bodies of water, and other types of terrain.
Occasionally, an aircraft may have an unintended encounter with terrain. When these events occur, investigations are performed to identify a cause for the unintended encounter with terrain. The analysis may be used to make improvements to aircraft, the operation of aircraft, and/or some combination of the two.
When identifying a cause for an unintended encounter with terrain, it is often desirable to locate the aircraft or any debris from the aircraft for analysis. An unintended encounter with terrain may result in debris including different structures from the aircraft. These structures may include, for example, without limitation, a wing, an engine, a section of the fuselage, a data recorder, and/or other components. The different structures may be analyzed to determine whether an inconsistency may have contributed to the unintended encounter with terrain. Data recorders may be used to analyze information that occurred during flight of aircraft. These data recorders may include audio recording devices that record conversation of the flight crew as well as ambient noise in the background of areas, such as the cockpit. Data recorders also may record data, commands, and/or other information sent between different computers and devices within the aircraft during flight. For example, data about positions of control surfaces, engine performance, temperatures, and/or other information may be obtained from these data recorders. These data recorders may be referred to as flight data recorders or black boxes.
Data recorders have signal transmitters. The signal transmitters may be used to locate the data recorders. In particular, these data recorders may include sound-based signal transmitters. These sound-based signal transmitters may be especially useful if the unintended encounter with terrain was in the form of a water environment.
When an aircraft has an unintended encounter with terrain in the form of a water environment, the different structures may quickly sink into the water. Some water environments may be especially deep such that visual identification of the aircraft by traveling over the location may not be possible. The sound transmitters used with the data recorders may be used to locate the data recorders in a water environment.
These data recorders, however, may only transmit sound signals for some limited period of time, because the data recorders rely on battery power. As a result, if the location of the debris for the aircraft cannot be located before the transmitter transmitting the sound signals depletes the power in the battery, finding the data recorders and other debris may be especially difficult. In some cases, the data recorders may not be found for years or may never be found. Further, because debris spread in a water environment is unpredictable, data recorders are often found in different areas from other aircraft structures. Without finding the debris, analysis of the unintended encounter with the water environment cannot be properly made in most cases.
Thus, it would be advantageous to have a method and apparatus that takes into account at least some of the issues discussed above as well as possibly other issues.